This invention relates to method for treating porous media to render such media relatively impermeable. More particularly this invention relates to methods for forming primary or secondary impermeable media barriers around subsurface and surface storage tanks such as used in filling stations for vehicles or in oil and gas refineries.
Environmental considerations have led to regulations on subsurface storage tanks for hydrocarbons or other chemicals, that such tanks have both a primary wall containment and a secondary wall containment to protect against failure of the primary wall containment. The present invention provides methods for treating, for example, older design, relatively porous, concrete hydrocarbon storage tanks internally to repair them and to vastly increase their impermeability. Similarly, the techniques of the present invention can be used to create secondary permeability barriers in the relatively porous soil surrounding such subsurface tanks by treating the surrounding soil itself prior to the installation of such a tank. In yet another application the methods of the present invention can be used to mix with aggregate material to form a relatively impervious or impermeable cement for use in forming either primary or secondary containment barriers in or about subsurface chemical or hydrocarbon storage tanks.